We will develop an instrument to improve the healthcare of the most frail members of the elderly community. This population; elderly or recovering patients living at home or in an extended care facility is too frail to leave this environment and, as such, is subject to significantly reduced physical activity. Although numerous studies have confirmed that continuous monitoring of daily energy expenditure and stride time variability would be a powerful tool in the effort to monitor vitality and to reduce fals among the elderly, subject compliance (getting people to consistently wear a monitoring device) has proven to be problematic. The objective of this program is to provide a remote, unattended monitoring system that identifies, records, and analyzes footstep patterns of multiple individuals simultaneously. Without the need to rely on subject abilities or compliance, this tool will quantif the total daily level of energy expenditure of individuals whose health limits their living environment to their home or to a nursing care unit. Temporal gait parameters, including gait variability, of these and more free-roaming individuals would also be made available by this system. Measurement of total daily energy expenditure due to walking will provide a view of each individual's day-to- day levels of activity. Changes in these levels are indicative of changes in health status while the gait variability measurements will provide an assessment of each individual's risk of falling. In summary we are proposing a shift in the monitoring of gait. By usig non-contact sensors and multi- individual recognition techniques, our system is unique in its ability to perform such monitoring without the need for subject compliance. Simultaneous data from multiple individuals will be parsed according to the specific walkers generating each gait sequence. Long-term, free-living monitoring, performed in the care facility or at the subject's home will provide early warning of decreasing health, fall risk estimations and objective measures of change as a result of medical intervention. PUBLIC HEALTH RELEVANCE: It has been demonstrated that the monitoring of gait in elderly individuals can provide valuable information regarding the overall health status and the likelihood for falling of these individuals. Unfortunately current approaches for effective, long-term monitoring require a high degree of subject compliance. We will develop and validate a gait monitoring system requiring minimal subject compliance. Successful completion of this program will greatly improve the likelihood of early, effective intervention in the care of the elderly including those among the most frail of this population.